Iran remains in compliance with the 2015 nuclear deal made with world powers, according to a UN atomic watchdog report.

The International Atomic Energy Agency (IAEA) said on Thursday that Iran's stock of low-enriched uranium is being used for peaceful purposes, and did not exceed the agreed limit of 300kg.

The report was the third since the January inauguration of US President Donald Trump, who has vowed to "dismantle" the "disastrous" accord between Iran and six major powers curtailing Tehran's atomic activities in exchange for sanctions relief.

Iran: US threats could lead to nuclear programme revival 'within hours'

While US sanctions imposed over Iran's nuclear activities remain suspended, Washington has ramped up others related to Tehran's support for "terrorism", its ballistic missile programme and its human rights record.

Iran says this contravenes the "spirit" of the deal, an accusation fired back by Trump at Tehran because of its funding and supplying of armed groups "across the region".

The 2015 accord covered only Iran's nuclear activities and the new IAEA quarterly report showed that these remained in compliance.

What the report says

The report did not explicitly say Iran is honouring the deal but mentions no deviations by Tehran, The Associated Press news agency said.

The confidential report obtained by various news organisations said the agency continues to hunt for "undeclared nuclear material and activities".

It added that Iran "has not pursued the construction of the Arak ... reactor" - which could give it weapons-grade plutonium - and has not enriched uranium above low purity levels.

The number of enrichment centrifuges also remained as agreed, while Iran's store of heavy water, a reactor coolant, was 111.0 tonnes after it exported 19.1 tonnes to an unnamed country.

Iran had previously inched above an agreed ceiling of 130 tonnes. The plant producing the heavy water was shut down for maintenance earlier this year and has now restarted, the IAEA said.

Trump is due in October to certify to Congress whether Iran is sticking to the nuclear deal. In July he told the Wall Street Journal he "would be surprised if they were in compliance".

As well as the United States, the hard-fought agreement also includes China, Russia, Britain, France and Germany. French President Emmanuel Macron said on Tuesday there is "no alternative" to the deal.

Tehran has warned that if the deal falls apart it can ramp up its atomic programme again within five days, giving Trump a second nuclear crisis to add to the standoff over North Korea.